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curriculum/challenges/english/blocks/learn-recursion-by-building-a-decimal-to-binary-converter/645b9d56b48971997a8055dd.md

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--description--

Within the body of the if statement, set the innerText property of result equal to the string "0". Then, use an early return statement to break out of the function early.

--hints--

You should set the innerText property of result equal to the string "0".

js
assert.match(String(decimalToBinary), /if\s*\(\s*input\s*===?\s*0\s*\)\s*\{\s*result\.innerText\s*=\s*('|"|`)\s*0\s*\1/);

After setting the innerText of the result element, you should use an early return statement to break out of the function early.

js
assert.match(String(decimalToBinary), /if\s*\(\s*input\s*===?\s*0\s*\)\s*\{\s*result\.innerText\s*=\s*('|"|`)\s*0\s*\1\s*;?\s*return\s*;?\s*\}/);

--seed--

--seed-contents--

html
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Decimal to Binary Converter</title>
    <link rel="stylesheet" href="styles.css" />
  </head>
  <body>
    <h1>
      Decimal to Binary 

      Converter
    </h1>
    <section class="input-container">
      <label for="number-input">Enter a decimal number:</label>
      <input
        value=""
        type="number"
        name="decimal number input"
        id="number-input"
        class="number-input"
      />
      <button class="convert-btn" id="convert-btn">Convert</button>
    </section>
    <section class="output-container">
      <output id="result" for="number-input"></output>
      <h2>Call stack</h2>
      <div id="animation-container"></div>
    </section>
    <script src="script.js"></script>
  </body>
</html>
css
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --light-grey: #f5f6f7;
  --dark-blue: #1b1b32;
  --orange: #f1be32;
}

body {
  display: flex;
  flex-direction: column;
  align-items: center;
  font-family: Menlo, Consolas, Monaco, Liberation Mono, Lucida Console,
    monospace;
  font-size: 1.125rem;
  color: var(--light-grey);
  background-color: var(--dark-blue);
  padding: 0 4px;
}

h1 {
  font-size: 2.125rem;
  text-align: center;
  margin: 20px 0;
}

h2 {
  font-size: 1.5rem;
  text-align: center;
  margin: 20px 0;
}

.input-container {
  display: flex;
  flex-direction: column;
  gap: 10px;
  justify-content: center;
  align-items: center;
  width: clamp(320px, 50vw, 460px);
  margin: 10px auto;
}

.input-container label {
  white-space: nowrap;
  word-spacing: -6px;
}

.convert-btn {
  font-size: inherit;
  font-family: inherit;
  background-color: var(--orange);
  width: 100%;
  height: 2rem;
  padding: 0 6px;
  border: none;
  border-radius: 2px;
  cursor: pointer;
}

.number-input {
  font-size: inherit;
  padding: 0.3rem;
  width: 100%;
}

.output-container {
  margin-inline: auto;
  width: clamp(320px, 50vw, 460px);
}

#result {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  text-align: center;
  min-height: 80px;
  margin-block-start: 20px;
  padding: 15px;
  border: 2px solid var(--orange);
  border-radius: 2px;
}

#animation-container {
  display: flex;
  flex-direction: column-reverse;
  justify-content: end;
  gap: 1rem;
  margin-block-end: 1rem;
  min-height: 40vh;
  border: 2px dashed var(--orange);
  padding: 1rem;
}

.animation-frame {
  font-family: -apple-system, BlinkMacSystemFont, avenir next, avenir, segoe ui,
    helvetica neue, helvetica, Cantarell, Ubuntu, roboto, noto, arial,
    sans-serif;
  padding: 15px 10px;
  border: 5px solid var(--orange);
  font-size: 1.2rem;
  text-align: center;
}

@media screen and (min-width: 36em) {
  body {
    font-size: 1rem;
  }

  .input-container {
    flex-direction: row;
    width: unset;
  }

  .number-input {
    width: unset;
  }
}
js
const numberInput = document.getElementById("number-input");
const convertBtn = document.getElementById("convert-btn");
const result = document.getElementById("result");

const decimalToBinary = (input) => {
  const inputs = [];
  const quotients = [];
  const remainders = [];

  --fcc-editable-region--
  if (input === 0) {
  }
  --fcc-editable-region--

  while (input > 0) {
    const quotient = Math.floor(input / 2);
    const remainder = input % 2;

    inputs.push(input);
    quotients.push(quotient);
    remainders.push(remainder);
    input = quotient;
  }

  console.log("Inputs: ", inputs);
  console.log("Quotients: ", quotients);
  console.log("Remainders: ", remainders);

  result.innerText = remainders.reverse().join("");
};

const checkUserInput = () => {
  if (
    !numberInput.value ||
    isNaN(parseInt(numberInput.value)) ||
    parseInt(numberInput.value) < 0
  ) {
    alert("Please provide a decimal number greater than or equal to 0");
    return;
  }

  decimalToBinary(parseInt(numberInput.value));
  numberInput.value = "";
};

convertBtn.addEventListener("click", checkUserInput);

numberInput.addEventListener("keydown", (e) => {
  if (e.key === "Enter") {
    checkUserInput();
  }
});